Plug and play distributor

Minimum components? If your distributor doesn't have a jammed advance mechanism or shot bearings, replace the pick-up and wire it to a 4 pin HEI module. This takes the ballast resistor out of the picture and is a simple, compact build.

Others have mentioned @halifaxhops offering custom curved distributors. A good advance curve is critical. The minimum parts count option there would be with a Pertronix Ignitor II (going with the II to take the ballast resistor out of the picture while allowing use of a normal tach).